Hi Andre, On Wed, Oct 07, 2015 at 03:55:10PM +0100, Andre Przywara wrote: > Hi, > > another respin and rebase of the ITS emulation series. > Major changes compared to v2 (beside some minor things like added > comments and function renames) are the rebasing and adaption to 4.3-rc > and Christoffer's timer rework series. Also the locking has been > reworked to cope with the dependencies of the its and the dist lock > in connection with the PROPBASER/PENDBASER and the command handling. > For a more detailed changelog see below or look at the respective > commit messages. > > This should address most of the comments I got on the list. > Many thanks to the diligent reviewers! > I didn't bother to fine-tune patch 01/16 too much, as I guess there > will be more discussion around this based on Pavel's latest post. > > These patches go on top of Christoffer's timer rework series [1], > which itself is on top of 4.3-rc2. > You can find all of this code in the its-emul/v3 branch of my > repository [2]. Thanks for rebasing the series! Just a heads up that I may not be able to review this series for the next 1-2 weeks, so I'm afraid it's not going to make it in for v4.4, sorry. Please let me know if this breaks expectations from everyone. Othersie, I will try review it with due dilligence so it makes it in for v4.5. Best, -Christoffer > > Changelog v2..v3: > - adapt to 4.3-rc and Christoffer's timer rework > - adapt spin locks on handling PROPBASER/PENDBASER registers > - rework locking in ITS command handling (dropping dist where needed) > - only clear LPI pending bit if LPI could actually be queued > - simplify GICR_CTLR handling > - properly free ITTEs (including our pending bitmap) > - fix corner cases with unmapped collections > - keep retire_lr() around > - rename vgic_handle_base_register to vgic_reg64_access() > - use kcalloc instead of kmalloc > - minor fixes, renames and added comments > > Changelog v1..v2 > - fix issues when using non-ITS GICv3 emulation > - streamline frame address initialization (new patch 05/15) > - preallocate buffer memory for reading from guest's memory > - move locking into the actual command handlers > - preallocate memory for new structures if needed > - use non-atomic __set_bit() and __clear_bit() when under the lock > - add INT command handler to allow LPI injection from the guest > - rewrite CWRITER handler to align with new locking scheme > - remove unneeded CONFIG_HAVE_KVM_MSI #ifdefs > - check memory table size against our LPI limit (65536 interrupts) > - observe initial gap of 1024 interrupts in pending table > - use term "configuration table" to be in line with the spec > - clarify and extend documentation on API extensions > - introduce new KVM_CAP_MSI_DEVID capability to advertise device ID requirement > - update, fix and add many comments > - minor style changes as requested by reviewers > > --------------- > > The GICv3 ITS (Interrupt Translation Service) is a part of the > ARM GICv3 interrupt controller [4] used for implementing MSIs. > It specifies a new kind of interrupts (LPIs), which are mapped to > establish a connection between a device, its MSI payload value and > the target processor the IRQ is eventually delivered to. > In order to allow using MSIs in an ARM64 KVM guest, we emulate this > ITS widget in the kernel. > The ITS works by reading commands written by software (from the guest > in our case) into a (guest allocated) memory region and establishing > the mapping between a device, the MSI payload and the target CPU. > We parse these commands and update our internal data structures to > reflect those changes. On an MSI injection we iterate those > structures to learn the LPI number we have to inject. > For the time being we use simple lists to hold the data, this is > good enough for the small number of entries each of the components > currently have. Should this become a performance bottleneck in the > future, those can be extended to arrays or trees if needed. > > Most of the code lives in a separate source file (its-emul.c), though > there are some changes necessary both in vgic.c and vgic-v3-emul.c. > > Patch 01/16 gets rid of the internal tracking of the used LR for > an injected IRQ, see the commit message for more details. > Patch 03/16 extends the KVM MSI ioctl to hold a device ID. > Patch 04-06 make small changes to the existing VGIC code which make > adaptions to the ITS later easier. > The rest of the patches implement the ITS functionality step by step. > For more details see the respective commit messages. > > For the time being this series gives us the ability to use emulated > PCI devices that can use MSIs in the guest. Those have to be > triggered by letting the userland device emulation simulate the MSI > write with the KVM_SIGNAL_MSI ioctl. This will be translated into > the proper LPI by the ITS emulation and injected into the guest in > the usual way (just with a higher IRQ number). > > This series is based on 4.3-rc2 and can be found at the its-emul/v3 > branch of this repository [2]. > For this to be used you need a GICv3 host machine (a fast model would > do), though it does not rely on any host ITS bits (neither in hardware > or software). > > To test this you can use the kvmtool patches available in the "its" > branch here [3]. > Start a guest with: "$ lkvm run --irqchip=gicv3-its --force-pci" > and see the ITS being used for instance by the virtio devices. > > [1]: https://git.linaro.org/people/christoffer.dall/linux-kvm-arm.git/shortlog/refs/heads/timer-rework-v3 > [2]: git://linux-arm.org/linux-ap.git > http://www.linux-arm.org/git?p=linux-ap.git;a=log;h=refs/heads/its-emul/v3 > [3]: git://linux-arm.org/kvmtool.git > http://www.linux-arm.org/git?p=kvmtool.git;a=log;h=refs/heads/its > [4]: http://arminfo.emea.arm.com/help/topic/com.arm.doc.ihi0069a/IHI0069A_gic_architecture_specification.pdf > > Andre Przywara (16): > KVM: arm/arm64: VGIC: don't track used LRs in the distributor > KVM: arm/arm64: remove now unused code after stay-in-LR rework > KVM: extend struct kvm_msi to hold a 32-bit device ID > KVM: arm/arm64: add emulation model specific destroy function > KVM: arm/arm64: extend arch CAP checks to allow per-VM capabilities > KVM: arm/arm64: make GIC frame address initialization model specific > KVM: arm64: Introduce new MMIO region for the ITS base address > KVM: arm64: handle ITS related GICv3 redistributor registers > KVM: arm64: introduce ITS emulation file with stub functions > KVM: arm64: implement basic ITS register handlers > KVM: arm64: add data structures to model ITS interrupt translation > KVM: arm64: handle pending bit for LPIs in ITS emulation > KVM: arm64: sync LPI configuration and pending tables > KVM: arm64: implement ITS command queue command handlers > KVM: arm64: implement MSI injection in ITS emulation > KVM: arm64: enable ITS emulation as a virtual MSI controller > > Documentation/virtual/kvm/api.txt | 14 +- > Documentation/virtual/kvm/devices/arm-vgic.txt | 9 + > arch/arm/include/asm/kvm_host.h | 2 +- > arch/arm/kvm/arm.c | 2 +- > arch/arm64/include/asm/kvm_host.h | 2 +- > arch/arm64/include/uapi/asm/kvm.h | 2 + > arch/arm64/kvm/Kconfig | 1 + > arch/arm64/kvm/Makefile | 1 + > arch/arm64/kvm/reset.c | 8 +- > include/kvm/arm_vgic.h | 43 +- > include/linux/irqchip/arm-gic-v3.h | 14 +- > include/uapi/linux/kvm.h | 5 +- > virt/kvm/arm/its-emul.c | 1187 ++++++++++++++++++++++++ > virt/kvm/arm/its-emul.h | 55 ++ > virt/kvm/arm/vgic-v2-emul.c | 3 + > virt/kvm/arm/vgic-v2.c | 1 + > virt/kvm/arm/vgic-v3-emul.c | 101 +- > virt/kvm/arm/vgic-v3.c | 1 + > virt/kvm/arm/vgic.c | 292 +++--- > virt/kvm/arm/vgic.h | 3 + > 20 files changed, 1601 insertions(+), 145 deletions(-) > create mode 100644 virt/kvm/arm/its-emul.c > create mode 100644 virt/kvm/arm/its-emul.h > > -- > 2.5.1 > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
